1. Field of the Invention
The present invention relates to a temperature controller for semiconductor devices, and more particularly to a temperature controller capable of accurately and simply controlling the temperature of a plurality of semiconductor devices.
1. Description of the Prior Art
As is well known in the art, semiconductor devices are widely used in various electronic components and devices such as transistors, integrated circuits, and the like. Many light beam scanners such as scanning recorders and scanning readers for deflecting and scanning a light beam with a light beam deflector employ semiconductor lasers as means for emitting such a scanning light beam.
In some applications, a plurality of semiconductor devices are used in combination to meet certain requirements. Specifically, a single continuous wave semiconductor laser which is available for use in light beam scanners has a power output ranging from at most 20 to 30 mW. Since the output energy generated by such a single continuous wave semiconductor laser is too small for a light beam scanner which requires a scanning light beam of high energy, a plurality of such semiconductor lasers of low energy output may be used in combination in a light beam scanner, and the laser beams emitted from the respective semiconductor lasers may be combined into a single laser beam for scanning a desired surface.
The semiconductor devices are highly temperature-dependent. It is necessary to effect highly accurate temperature control on certain semiconductor devices such as a semiconductor laser which must be as free as possible from output power changes dependent on temperature variations. Where a plurality of semiconductor devices are combined for an increased power output, it is desired that the temperature of all of the semiconductor devices be controlled highly accurately since even small errors in temperature control of the respective semiconductor devices would have a cumulative effect on the combined power output from the semiconductor devices. Since it would not be preferable in terms of cost to provide each of the semiconductor devices with means for effecting highly accurate temperature control, there has been a demand for a temperature controller for easily and inexpensively controlling the temperature of a plurality of combined semiconductor devices with high accuracy.